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Kathryn McDonough breaks down crying Wednesday while describing how she pushed Elizabeth “Lizzi” Marriott's body into the Piscataqua River and covered it with seaweed. McDonough is the state's key witness against her former boyfriend, Seth Mazzaglia, accused of killing and raping Marriott in his Dover apartment in October 2012. (Jim Cole/Associated Press/Pool)

Ex-girlfriend of Mazzaglia recounts Lizzi's final moments

By MIKE LAWRENCEUnion Leader Correspondent

Seth Mazzaglia, leaves the courtroom for the lunch break after listening to his former girlfriend describe the death of Elizabeth Marriott. (Jim Cole/Associated Press/Pool)

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DOVER — Kathryn “Kat” McDonough testified that she was sitting next to Elizabeth “Lizzi” Marriott when Seth Mazzaglia began strangling the 19-year-old with a white cotton rope.

McDonough said Marriott “almost immediately” stopped moving and gave only a “short ... quick gasp.”

In a quavering voice, McDonough testified Wednesday that as her boyfriend choked Marriott while wearing black leather gloves, she numbly rose and drew the curtains across the two windows in the Dover apartment she and Mazzaglia, 31, shared.

McDonough, 20, is serving a 1½- to three-year prison term after pleading guilty to charges including witness tampering and hindering the investigation. She has testified that she helped cover up the murder of Marriott, whose limp body she said Mazzaglia raped.

As prosecutor Peter Hinckley guided McDonough through the days following Marriott’s death on Oct. 9, 2012, McDonough admitted giving “false details” to investigators. Mazzaglia, facing first- and second-degree murder charges, sat impassively in Strafford County Superior Court throughout her testimony.

Hinckley pressed McDonough about her failure to call police, and her decision to remain in the apartment and not seek help.

“I didn’t have anywhere else to go,” McDonough said. “I loved (Mazzaglia), I didn’t want to lose him. He was the only real person I had.”

McDonough detailed how she and Mazzaglia gathered Marriott’s belongings, turned off Marriott’s cellphone and their own and wrapped her body in a tarp and a suitcase that wouldn’t entirely close.

“(Mazzaglia) held the suitcase shut while I wrapped the duct tape around,” McDonough said.

They then drove Marriott’s car on a circuitous route that ended at Peirce Island in Portsmouth, where McDonough said she and Mazzaglia struggled to push and drag Marriott’s body to a railing that overlooked a cliff.

McDonough said Mazzaglia lifted Marriott’s body and pushed it over the rail, but it landed on rocks. McDonough said she was the only one able to climb across rocks at water-level to Marriott’s body, which she said Mazzaglia asked her to cover with seaweed and try to push into the water.

She described that moment as “surreal,” as she looked down at someone with whom she had been playing a card game just hours before, worked with at Target in Greenland, and “enjoyed spending time with.”

“Her body was half-floating, covered in seaweed,” McDonough said. “I didn’t even know what to think. I felt so awful, so confused. I had so many conflicting emotions. Someone who brought so much joy to people’s lives — and there she was,” McDonough said.

She added: “So many things that she’s never going to be able to do,” McDonough said. “I’m only 20, but I still look back and think ... there’s still so much of life left. She never got to get married. She never got to have kids. It’s all because of us, that she never got to live her life,” McDonough continued, sobbing.

In opening statements May 28, defense attorney Joachim Barth told jurors it was McDonough, not Mazzaglia, who killed Marriott that night.

Mazzaglia was arrested on suspicion of murder Oct. 13, 2012. McDonough was arrested Dec. 24. Hinckley noted that McDonough’s original sentence for felony perjury and other charges was for up to 18 years and that she could return to jail for much of that time if she failed to meet her obligations in court.

“What is your primary obligation?” Hinckley asked.

“To tell the truth,” McDonough replied.

Hinckley asked McDonough if she killed Marriott, if Marriott died “accidentally or any other way,” or “in any sort of sexual activity in which she was a willing participant.” McDonough said “no” to all three.

McDonough said Mazzaglia strangled Marriott from behind with a rope while the three of them were watching a movie after a game of strip poker in which McDonough and Mazzaglia had ended up naked while Marriott remained in her underwear. Marriott told them it would not be OK for McDonough and Mazzaglia to have sex in front of her, McDonough testified.

“I told (defense investigators) that Lizzi willingly had sex with Seth and I, when she didn’t,” McDonough said. “I told them that ropes were tied on to her for bondage, which didn’t happen. I told them that the strip poker had actually led to things ... like there was provocative dancing and things like that,” McDonough continued, saying that also was untrue.